科学美国人60秒:Ozone Hole Closing Up, Thanks to Global Action

The fragile layer of gas that protects all living things on Earth from the sun's harsh ultraviolet light is on the mend—in other words, the ozone hole is healing. That's according to the latest assessment by the World Meteorological Organization and the United Nations Environment Programme.

The ozone hole had been growing for decades over Antarctica. But the world recognized the problem and took action more than a quarter-century ago. The 1987 Montreal Protocol phased out the use of chlorofluorocarbons, or CFCs, responsible. With the ozone-damaging compounds gone, the layer had a chance to recover and the hole is no longer growing.

A bonus: the phase-out also helped slow global warming. Because CFCs are also powerful greenhouse gases. In fact, the agreement to address the ozone hole has actually cut five times the greenhouse gas emissions as has the Kyoto Protocol to address global warming.

The Montreal Protocol shows that the world can come together to deal with global environmental problems. The protocol also illustrates that actions may require decades to yield results. Which drives home the need to address our climate crisis now.   

—David Biello